Methods, systems, and apparatus, including computer program products are described for calibrating servos, and in some implementations, calibrating spiral servos for use in self-servo-write SSW processes. In one aspect, a method is provide that includes rotating a machine readable medium, and detecting a spiral on the machine readable medium. Detecting a spiral on the machine readable medium includes detecting magnitudes of the spiral and a timing mark, storing a timestamp from a clock signal that corresponds to the timing mark of the spiral, determining a peak of the spiral from the magnitudes, and locking the clock signal to the peak of the spiral using the timestamp.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An apparatus comprising: a servo track detector that detects a spiral on a machine readable medium; a clock generator that generates a clock signal and locks the clock signal to timing marks of the spiral to calibrate an average spiral peak time; and a servo track window period generator that generates a spiral window to determine a location of the spiral using the average spiral peak time.
2. The apparatus of claim 1 , wherein the servo track detector includes a detection module that determines spiral peak times using the spiral window.
3. The apparatus of claim 2 , wherein the servo track detector further includes a comparison module that determines a timing offset between the clock signal and the timing marks of the spiral.
4. The apparatus of claim 1 , further comprising: a servo track generator that generates servo tracks using the spiral.
5. The apparatus of claim 1 , further comprising: an error correction module that applies repetitive error control.
6. A method comprising: seeking to an inner diameter of a machine readable medium; detecting a spiral on the machine readable medium; locking a clock signal to timing marks of the spiral including calibrating an average spiral peak time using the clock signal; determining a location of the spiral using the average spiral peak time; and calibrating a spiral servo according to the location of the spiral.
7. The method of claim 6 , wherein seeking to an inner diameter includes seeking to a crash stop of the machine readable medium.
8. The method of claim 6 , further comprising: seeking away from the inner diameter of the machine readable medium; and writing servo tracks using the spiral servo.
9. The method of claim 6 , wherein locking the clock signal to timing marks further includes: applying repetitive error control.
10. A system comprising: a machine readable medium; and a servo controller including: a servo track detector that detects a spiral on the machine readable medium; a clock generator that generates a clock signal and locks the clock signal to timing marks of the spiral to calibrate an average spiral peak time; and a servo track window period generator that generates a spiral window to determine a location of the spiral using the average spiral peak time.
11. An apparatus comprising: a servo track detector that detects a spiral on a machine readable medium; a clock generator that generates a clock signal and locks the clock signal to timing marks of the spiral to calibrate an average spiral peak time; and means for generating a spiral window to determine a location of the spiral using the average spiral peak time.
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August 15, 2008
September 20, 2011
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